Active reading of conventional, paper documents often involves marking or annotating text by a reader as they read using a number of methods, the most obvious of which is to highlight the text to or place a written notation adjacent to the text. Typical annotations include margin notes, vertical bars, graphic notations, highlights, underlines, circles, etc. References to external documents (ex: hypertext documents, footnotes, etc.) in text generally stand out due to their grammatical citation which creates a visual and contextual distinction from the surrounding text.
There are several currently existing techniques available to users for annotating documents. For example, methods exist for annotating online documents using a web browsing facility, electronic meeting systems (e.g. the “whiteboard” feature in Microsoft's Netmeeting™), and through word processing software. In some of the more basic systems, annotation of documents may comprise manually listing the documents (by writing on paper, using the cut and paste feature of an operating system clipboard, or using the book marking function of the browser), none of which leaves a persistent trace within the displayed document.
More advanced annotation techniques exist for digitally marking documents, such as the method of digital ink as described in Schilit et al., Beyond Paper: Supporting Active Reading with Free Form Digital Ink Annotations, Proceedings of CHI98. These more advanced systems reduce the amount of reader interruption which often results from basic annotation techniques.
Systems also exist for detecting the annotation context and organizing those annotations for the user by displaying a list of just the annotated passages. For example, in U.S. Pat. No. 6,279,014, filed Sep. 15, 1997, a technique for organizing annotations in the context of the document in which they appear is described. Other systems, such as the one described in U.S. patent application Ser. No. 09/222,962 filed Dec. 30, 1998, provide a method for maintaining freeform ink annotations on changing views. This technique involves maintaining freeform ink annotations on changing views by anchoring ink strokes to specific objects that can move around or change size.
Each of these techniques reduces reading interruption and provides readers with an overview of the annotated portions of a document. However, in electronic documents, users are often presented with the decision of whether to follow a link contained within the document or to continue reading. If a reader decides to follow the link, the current document is often replaced by the target document, thus interrupting reading flow. Alternatively, if the reader decides not to follow the link and continues reading, the reader may forget to return and follow the link, may be unable to remember why the link was interesting, or may not be able to locate the link.
Many strategies are used by readers presented with such decisions. One is the “read first, follow links later” strategy. Under this strategy a reader will read the entire document and then return and follow the links they found interesting. This strategy relies on a reader's ability to remember which links were interesting, and where in the document they were located.
Another strategy is to “follow links as they are encountered.” Using this strategy a user follows links they find interesting as they approach each link. In addition to interrupting the flow of reading, another problem with this strategy is that it may result in a reader losing track of the original document. Often when a link is followed the original document is removed from the viewing area and replaced with the target of the link.
Another strategy for managing the task of reading documents containing links is to gather the links using a link-gathering interface. Examples of conventional link gathering interfaces include the bookmark facility of Web browsers, and spatial hypertexts such as VIKI (Marshall, C. C., Shipman, F. M. III and Coombs, J (1994) VIKI: Spatial Hypertext Supporting Emergent Structure. In Proceedings of The European Conference on Hypertext 1994 (Edinburgh, Scotland September 19–23): ACM Press, 13–23.); Data Mountain (Robertson, G. G. (1998) Data Mountain: Using Spatial Memory for Document Management. In Proceedings of UIST98 (San Francisco, Calif. November 2–4), ACM Press, 153–162.); Web Squirrel (Bernstein, 1998, http://www.eastgate.com/squirrel/); and Web Forager (Card, S. K., Robertson, G. G., and York, W. (1996) The WebBook and the Web Forager: An Information Workspace for the World-Wide Web. In Proceedings of CHI96 (Vancouver, BC April 13–18), ACM Press, 11–117.). While this type of explicit link gathering may be less computationally intensive than annotation processing, it is more difficult on the user for whom annotation is a generally intuitive and well-honed skill.
Still other systems maintain annotations on Web pages that may change unpredictably, but such systems have not considered processing the annotations that are near anchors. For example, Equill visual markup, (www.equill.com), and I-markup (www.imarkup.com) associate freeform ink annotations with objects in a Web page, but do not allow a reader to manipulate documents based on these marks.
Additionally, a number of systems that provide hypertext graph searching capability have been described in literature (e.g., Consens, M. P., Eigler, F. Ch., Hasan, M. Z., Mendelzon, A. O., Noik, E. G., Ryman, A. G., and Vista, D. (1994) Architecture and Applications of the Hy+ Visualization System, IBM Systems Journal, 33 (3), 458–476). Such tools allow the user to pose queries and to manipulate documents based on hypertext topology to identify desired nodes based on graph connectivity.
Even with all these different techniques and strategies for making reading and annotating documents easier and more manageable, current techniques still either interrupt the reader's concentration or rely on the reader's ability to later locate the interesting links and remember why they were interesting.
Thus, there is a desire for a system which will allow a user to defer link following while not losing track of the links location within a document. Additionally, there is a desire for a system which extends beyond just explicit link gathering interfaces.